---
title: "Inductor in power of W5100"
url: "https://maker.wiznet.io/forum/9966"
markdown_url: "https://maker.wiznet.io/forum/9966/md"
type: "Forum topic"
category: "Ethernet Chips"
author: "mahdavifar"
created: "2014-02-21T10:07:12+09:00"
last_activity: "2017-05-04T08:31:36+09:00"
language: "en"
views: 543
replies: 3
source: "WIZnet Makers forum (https://maker.wiznet.io/forum/)"
---

# Inductor in power of W5100

## Question

Asked by mahdavifar on 2014-02-21 in Ethernet Chips.

Hi,

In W5100 schematic there is a inductor between analog and digital ground. What is its value?
Do I use a ferrite bead or I can use a normal inductor ?

Regards

## Replies

### Reply 1 by irinakim, 2014-02-24

Hi,

As far as I know, you have to use ferrite bead.
Because the inductor(FB2) was used “HB-1M1608-121” in the W5100E01- AVR schematic.
Please refer to as below.

Schematic : [url][http://www.wiznet.co.kr/UpLoad_Files/ReferenceFiles/SCHEMATICs_W5100E01-AVR.zip\[/url\]](http://www.wiznet.co.kr/UpLoad_Files/ReferenceFiles/SCHEMATICs_W5100E01-AVR.zip%5B/url%5D)
part list : [url][http://www.wiznet.co.kr/UpLoad_Files/ReferenceFiles/partlist_W5100E01-AVR.zip\[/url\]](http://www.wiznet.co.kr/UpLoad_Files/ReferenceFiles/partlist_W5100E01-AVR.zip%5B/url%5D)

thanks, ![:slight_smile:](https://emoji.discourse-cdn.com/twitter/slight_smile.png?v=12)

### Reply 2 by mahdavifar, 2014-02-24

Hi,
What is exact value of inductor FB2 in this circuit ? ( as you mentioned its part no. is “HB-1M1608-121” )
I saw in the schematic that the digital ground ( GNDD ) and analog ground ( GNDA ) pins of the chip is tied together. Is it right ? I must short these pins ?

Regards.

### Reply 3 by irinakim, 2014-02-25

Hi,

You have to use 0.5A or 0.3A/120 ohm or 60 ohm as Ferrite bead value and we use the “HB-1M1608-121”.
I recommend that these pins(GNDD/GNDA)is connected to Ferrite bead for stability.

thanks, ![:slight_smile:](https://emoji.discourse-cdn.com/twitter/slight_smile.png?v=12)

---

Source: https://maker.wiznet.io/forum/9966